As one of wearable terminals that a user wears and uses, there is a head mounted display (hereinafter, referred to as “HMD”). The HMD is a display device that is mounted on the head of a user when used and in recent years, the HMD is not only used as AV equipment and a display device for a computer game and the like. but also used as a display device for a user to check information while working in working environment.
For example, on a medical site, the HMD is used as a display device for displaying an image of an endoscope (for example, Patent Literatures 1 and 2). An operator wears the HMD and performs an operation while viewing an image displayed on the HMD. In the past, an image of the endoscope was usually displayed on a monitor installed in the vicinity of the operator, and therefore, it was necessary for the operator to frequently move his/her visual line between the monitor and a patient. By displaying the image of the endoscope on the HMD, it is made possible for an operator to check the image of the endoscope displayed on the display unit of the HMD and a patient without moving his/her visual line considerably.